Okay so, I'll try to explain to you all why I have certain cvars set to X, Y or Z and why after all these years playing quake I think I finally managed to get pretty much the perfect config (at least for me).

Okay, so, I begin :

MOVEMENTS BINDS:
As you might already know, I'm not using a standard binds configuration for movements and weapons. In fact I have R to move left, H to move right, T to move forward and G to move backward. I use this configuration because it makes my hand and fingers more relaxed and the position of them on my keyboard feels more natural. I have also plenty of keys available around "R T G H", much more than compared to standard "W A S D". Actually I even have 5 keys that I can press only with my little finger (S for RL, X for PG, Z for HMG, W to walk and finally A to crouch), leaving free my others fingers.
I'm playing with this binds for years and years now, never ever went back to "W A S D", since I discovered it, I got addicted pretty fast :), actually it works VERY well.

COLORED GRENADES (AND RAIL):
I have my own grenades set to cyan (color of my crosshair), enemies grenades set to light green (enemymodelcolor) and team mates grenades set to red (teammodelcolor). This way I can easily recognize if I can rush a choke point with plenty of nades spammed. If I see them red then I can move forward, if I see them light green, I have to be more careful :).
I have also the same set of colors for rail.

HUD:
I use the default hud3, which is the big one made by QL devs, it has big health and armor indicators, the scores at the bottom right corner are easy to read, the clock however seems a bit too small but I can deal with it :). It's a nice hud because you can easily see if you're low hp and then +back etc. It has also color indicators such as white for lot of hp, yellow for 100hp and less and finally red for less than 25 hp. I like the fact that the hp and armor numbers are BIG, because you don't constantly look at them with your, what I would call, "focus vision". When you're engaging a shaft battle for example, your focus vision is locked at the enemymodel, but because the hp and armor numbers are big, you still see the colors etc with your "peripheral vision".
I have also the weaponbar on the middle left of my screen, so that basically every hud elements are placed all around the sides of the screen, leaving the middle of the screen almost perfectly empty for better visibility and focus on my crosshair. Also I found that placing the weaponbar in bottom middle of the screen can cause some misreading with the shaft beam and the fact that it's put horizontally makes it a bit slower to read than when it's put vertically.

DRAW AMMOS WARNING, DRAW FRAG MESSAGES, DRAW REWARDS:
I have all disabled, because I have a sound when ammos start to get low, so the low ammo message would be redundant. And for frag message I don't need it because you have the kill beep sound with darken dead bodies and also an obituary at the top right corner of the screen.
And about the rewards like "impressive", "excellent", "headshot", "combokill" etc... I don't need it to be shown because I can hear the vadrigar voice over :). So there again, less messages/icons at the center of my screen, leaving all the space to focus on my target.

RAIL TRAIL, LG BEAM AND WEAPONS IN GENERAL:
I personally use lightningstyle 4, which is the thinnest beam of all the beams available, with drawgun 3 (static weapons and translucent so that it doesn't obstruct my view).
Also the LG beam can be considered as part of the crosshair, so when it's thin, it's like adding a straight line from bottom-right/left/middle (depending if you show the guns or not or on the position of your guns on the screen) to center of the screen; it can help a bit for aiming.
Having the weapons shown is personal preference I guess, but I personally like a lot drawgun 3 (you have the weapons shown but translucent and the feeling is nice with big models @ FOV 90). If you show the guns, if you're left-handed, make sure to set them on the left, and if right-handed, obviously on the right, it will feel more natural this way. Don't put them in the middle of the screen, it gives bad habits and basically no other FPSs outside of the Quake franchise allow you to show the gun in the middle of the screen. You can still put them in middle if you only play quake ofc :), but I heard Diabotical won't allow to hide the guns and probably won't allow to put them in the middle of the screen either (hope 2GD will reconsider it tbh :D). And we don't know yet about QUAKE Champions :).
Truelightning MUST be set to 1 if you don't have a ping above 80ms (when the unlagged stops working). For example with 50ms all you have to do is putting your crosshair at the middle of the enemymodel, no need to anticipate the players movements like in the old days in Q3 OSP or RA3.
For the rail, I have just a translucent trail without any other bullshit and gimmicks effects like the circle around the trail or shit like these :p. Actually I have the default Q3 beam, which is perfectly fine as it is :).

CHATS BEEPS AND CHAT IN GENERAL:
I have a beep sound indicator only for team messages, this way if people in spec are chatting constantly you don't get the annoying beep everytime. And in team gametypes, when you hear the beep, it means that it's probably an important message like "enemy low!" or "escaping high" and so on...
Also I've set the teamchattime to last longer after the message is wrote.
And finally when I press +chat (bound to 3) I get 8 lines instead of the default 6.

MODEL, ENEMYMODEL AND TEAM MODEL (+ colors):
I have phobos as own model because I just like his orange suit and I like the sounds he makes while jumping, getting low on health etc. It's very short and soft sounds (also, cooller used to play with doom for years :D).
I have light red crash as teammodel, because it's the thinnest model in the game along with bones. And doom and crash could start a love story together :D, they look the same except that they male and female xD. I like crash because when you're behind a team mate you can still see the enemy in front of your mate, unlike with tankjr who probably takes 80% of the screen :D. I like also having different sounds for myself, my team mates and the enemies.
I use keel as enemymodel with lodbias set to -2. This way it's a bit bigger keel and it fits the hitbox better.
Light green as enemymodel color, pretty standard, nothing special here :).
"Tankjr gives you the illusion you hit more" (c) idoser ---> He's right, if the model is bigger it doesn't necessarily mean that you'll hit it more easily, mainly because of the hitbox size, which stays the same.
And about the "yeah but with tankjr it's easier to hit pixel rails when enemy is hidding behind pillar or wall", I asked sponge about that, and he said to me that it's only 1 frame difference with keel, so let's say it's pretty much unoticeable. It doesn't give you any considerable advantage compared to keel.
And somehow I shaft better keel at close range than I do with tankjr. And I'm used to keel, it fits the hitbox very well, it's not to small nor big, just perfect really.
So I say it : keel > tankjr :)

DEMOS RECORD MESSAGE:
Set to 2, means that you don't get the whole "recording demo xxxxxxxx" message at the bottom of the screen, instead, you get a very unobtrusive "REC *" at the bottom left corner of the screen.

FOV AND ZOOMFOV:
Fov 90. Zoomfov 40 with instant zooming (no zoomScaling, which mean that when you press the zoom key (for me it's bound to spacebar) the zoom effect is 100% instant.
Zoomfov 40 only for long range rails. Fov 90 for all weapons.
I played for years and years with fov 100 and probably 2 years ago wanted to try lower fov. Tried 90, liked it, kept it up until now :D.
Why do I prefer fov 90 over any other fov ? Firstly because it's a very common and standard fov in basically 90% of the FPS on PC (not consoles, PC). CS has it to 90, TF2 aswell, bioshock, stalker, dishonored, rage, even doom, all those games have fov 90, and plently plently others fps games too. I think there's a reason why the standard fov is always 90, actually I think there are 2 main reasons : everything on the screen appears bigger (the environment, the models etc) and there's less "distortion" at the sides of the screen.
So yeah, bigger enemymodel, less distortion of the image, and also 1 last thing : it's easier and more visible to make tiny mouse's movements with a low fov than with a high fov. The mouse feels more responsive and fast. Combine fov 90 with high sens (which is my case), and you get maximum precision for small mouse's movements :).
And I think there's a reason why most of the pro players abuse the zoom. Fov 90 is actually like a minizoom :).
Oh and also, it makes medium/long range shaft battles a bit easier too :), which in my case is very important :D.

SIMPLE ITEMS:
Quakelive's simple items are actually very nice, they are clear, they look cool. I use it. I've made the icons slightly bigger and I disabled the bobbing except for the major items like RA or MH, this way I can see the RA on bloodrun when I'm at the shards, because of the simple item size and bobbing (not for the shards, just for RA MH YA etc, like I said)

DISABLING ALL THE USELESS AND DISTURBING EFFECTS:
impact, muzzleflash, shadows, dynamiclights, smokes, bubble trail(in water), lightningimpact (no need for it since you have the crosshair that blinks/changes color when you hit + hitsounds), sparks, damageplum (except for rockets, nades, plasmagun, shotgun and bfg) damageblend, all these useless effects are disabled in my config. I want the cleanest and most "pure/raw" config possible. Not a single distracting effect. Basically everything is removed, but I can't list it there cause can't remember some cvars :D.
The less distracting effects you get, the better, I think a lot of people will agree with me on this :D.
Less is more (c) Axe

CONSOLE:
I have a plain black console background for better readability, and I have also console speed set to 1000 so that when you press the console bind it pops up instantly.

PERFORMANCE CVARS:
r_enablePostProcess 0
r_enableColorCorrect 0
r_enableBloom 0
r_ext_compressed_textures 1
If your PC is quite old or just not so powerful then adding these console commands might help you to get higher and more stable fps. And I personally don't give a shit about postprocess, bloom and colorcorrect, quake 3 looked good enough without it :D. More FPS always better than better look :).

VISUALS, PICMIP:
I play with vertexlight, since it gives a significant fps boost and I like the consistent look of vertex compared to lightmap, I mean, if you configure the right way your vertex settings, you can get pretty much the same color intensity and "lighting" for all the maps. While in lightmap some maps are much brighter or darker than others. Also, with lightmap and high picmip you get some VERY ugly and distracting shadows. It's not the case with vertexlight.
With mapoverbrightbits set to 8 and mapoverbrightcap set to 145 you get a very smooth and consistent visual for ALL the maps.
I use picmip 16. I like when it looks very clean without any textures on the maps.
I have also texturemode set to "gl_linear", which is basically anisotropic-filtering 8x/16x, so that I have a thinner lg beam at long range and the enemymodels are fully textured at any range, which makes a nice contrast with the "textureless" maps.
That way I can focus on the enemymodel at 100%.
Oh and also, I can see perfectly the jumppads even at very long range :).

PLAYERLEAN:
Set to 0. Playerlean is useless. Some people say it's easier to aim with player lean 1 because you see better where the enemymodel goes, so you can adjust your aim in consequence. Bullshit. Playerlean is just distracting nothing else. And also it makes the model go out of the hitbox especially at relatively high moving speed. With playerlean 0 the model NEVER goes out of the hitbox, and like I said it's much less distracting. I tried to play with playerlean 1 after years of playerlean 0, I had hard time to aim properly at the center of the enemymodel xD.
Also, quakeworld players still hit 60%+ LG without playerlean. Purri and Damiah can still rail 60% in quake 2 without playerlean :). And afaik CS doesn't have playerlean either and yet skilled people can aim and predict the movements very well still.

CROSSHAIR:
I discovered quake 3 for the first time in 2002 or something. Been playing quake on & off for more than 10 years now, so yes, I'm not the oldest quake player but I can still be considered a veteran. Over all these years I tried EVERY crosshairs you can imagine. And guess what ? One word: simplicity. I figured out that the simplest, most effective and generic crosshair is crosshair 11, a simple dot with black outline.
And because I'm playing with what we can consider to be a low fov (at least for quake players), I like my crosshair to be small but visible (so that I can see it perfectly even with my "peripheral vision", and it gives me maximum precision for long range shots and tiny mouse's movements). Also, at my resolution (1920x1080) crosshairsize 18 is "sharper", the black outline and the rest of the crosshair are more clear and visible.
With a simple small but visible dot, you get maximum precision without any crosshair overlapping.
Also I noticed that when I aim at the enemy, I don't look at my crosshair (or very rarely), so my "focus" vision is on the enemymodel. Then it makes sense to have a cyan/white & sharp dot with black outline so that you can see it better in any situation with your "peripheral" vision. Better for flick shots, to say the least.
I found out that crosshair 11 at size 18, and fov 90, is almost perfect in any situation with any weapon, especially at medium/long/very long range.
And finally my crosshair color is cyan because it's a very light color and it's smooth for the eyes. And I have crosshairhitcolor set to white, because if I set it to red I find it too distracting, I mean cyan is a closer color to white than it is to red, the contrast between red and cyan is just too much. Cyan and white work well together imho :).

SENSITIVITY:
I'm using high sensitivity for like 6 or 8 months now (14.4cm/360°, no accel). I was using low/very low sens (30+cm/360°) for years and years before it. I also tried med sens for like 2 or 3 years (23.1cm/360°). I have played with all different types of mice, from kinzu v1 with accel, to deathadder, mx310, diamondback, FK etc. I'm now playing with the ZowieByBenQ EC2-A at 1600dpi. If I were using low/very low sens I would've used 400dpi, if I were playing with very/ultra high sens, then I would have used 3200dpi. I think that for high sens (between 10cm and 15cm), 1600dpi works best (so yeah, middle/high dpi value). Also, at windows and in the QL menu, especially with full HD res (1080p), it's much more comfortable to have a relatively high dpi value, because obviously the mouse moves faster, it's more reactive. And for games like starcraft or mobas, having a higher sens without changing the windows sens (6/11) feels much better.
You would obviously probably ask me why I'm that crazy to use a high sens ?
CZM at his prime used high sens, latrommi is using high sens, rapha too, and one of my friend which is very very good at half-life 1 deathmatch and overwatch is also using high sens. As long as it's not extreme high sens (like 3cm or 5cm), it's still rather easy to control it once you get used to it. And it reacts much faster than very low sens (35+cm), it gives you more "freedom" in your movements too. And you almost don't get uncomfortable hand position on the mousepad while tracking with LG, unlike with low sens (even med sens tbh, 20cm-25cm). If you're very focused and slightly relaxed, you do your mouse's movements effortlessly, unlike with low sens. And no, you're not worst at long range compared to low sens, it's just a myth :). Maybe with ultra high sens, long range can be a problem, but with high sens, you can just aim as good with it as with low sens, but with less effort :). I'm actually still better at med-long range than close range, with high sens :).
TBH, I think the perfect sens value is between 10cm and 15cm.
Oh, and don't use accel, it's evil :).

I've been thinking a lot about what would be the best xhair and came to the conclusion that xhair 2 with infared is theoretically the best. Anything else such as colour and adding circles is just preference. Because with the horizontal and vertical llnes you are able to line up against the walls easily and you want it decently big (i use 33) because it can become difficult to see close range but not too big that it often obscures your view against the enemy model. But i discovered one major problem with this xhair which is that the xhair can block the view of your enemy. Zoom and xhair 3 only partially fix these problems and each requires certain methods to reduce the issue (such as zooming before enemy comes, alligning xhair to correct position so xhair is not blocking the view etc) and no crosshair will ever fix the corner problem where your xhair is in the corner and the tip of the enemies head is there. Ofc these issues are minimal and unlikely to happen but they still exist, especially for ppl who don't zoom.

The reason rather is that with postprocess you can have way better ejemy<>map contrast levels. So unless your pc cant handle the impact on fps levels theres no reason not to go for that var with high visibility in mind

r_ignorehwgamma 1 is usually the culprit that people use that makes ingame colors bland/desaturated (there are other settings that could have the same visual effect). And if you check most pro's configs, they have it set to 1. Which makes no sense because I do believe enabling PP basically overrides the ignorehwgamma setting. So it's like having it set to 0 to begin with. With the added risk of running into performance issues having PP enabled.

Never really understood what ignorehwgamma did other than reduce contrast and saturation. I've always had it set to 0 and never had a problem getting enemy models bright.

and thats exactly what im saying, its not possible to achieve the postprocess contrast no matter what settings. you can get decent contrast out of pp1, but it will never be on the level possible by pp1

Postprocessing is not enabled in either of the two configs I linked to. They have every bit of contrast and bright enemy skins as any sane postprocessing settings can give you. I went through it all years ago, comparing different settings. There's visually no difference between those settings I was using and enablepostprocess 1.